Technical Field
The present disclosure relates to a control apparatus for a rotating electric machine that controls a synchronous rotating electric machine. In particular, the present disclosure relates to detection of a rotation angle of a rotor.
Related Art
A control apparatus for a synchronous rotating electric machine, such as a brushless direct-current (DC) motor, controls the rotating electric machine by manipulating a voltage supplied to the rotating electric machine based on a rotation angle of a rotor. A configuration of the control apparatus of a synchronous rotating electric machine is known in which the rotation angle of the rotor is detected based on periodic changes in voltage at a neutral point of an armature winding. For example, in a configuration described in Japanese Patent Publication No. 3424307, a resistor circuit that has a three-phase star connection is provided in parallel with an armature winding that has a three-phase star connection. An induced voltage generated in the armature winding is acquired based on a deviation between the voltage at the neutral point of the armature winding and the voltage at the neutral point of the resistor circuit. The rotation angle of the rotor is then detected based on the detected induced voltage.
Double-layer winding-type rotating electric machines have been used in recent years. In double-layer winding-type rotating electric machines, three-phase windings are doubly disposed with a phase difference of 30 degrees so as to cancel out sixth-order components of a reaction magnetomotive force that is a main cause of magnetic noise in a rotating electric machine for vehicles. A proposal for a new technique for this type of multilayer winding-type rotating electric machines is desired to be applicable to a configuration in which a rotation angle of a rotor is detected based on period changes in voltage at a neutral point of an armature winding.